I've edited in the Ninfinger images from the 1983 catalog... and noticed something else that really casts doubt on the PNC-55AC being used with the Magnum Sprint. If you look at the Magnum Hornet on the same page, it clearly has a PNC-55AC nosecone, and it looks nothing like the Sprint's nosecone.

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Dreaming of making the rockets I dreamed of as a kid (and then some).

"The Guide says there is an art to flying", said Ford, "or rather a knack."
"The knack lies in learning how to throw yourself at the ground and miss."

Launching is Optional... Landing? That Depends on Trees.